There is big demand in industrialized countries for oil products, as is known, and more specifically to the necessity to transport oil in significant quantities, including by means of water transportation. At the same time, technological processes, which involve oil extraction, oil processing, transportation and storage of oil products constitute one of the most anthropogenous reasons for mass pollution of water surfaces. Besides, special danger stems from accidents which occur on oil pipe lines, since oil pollution due to an accident differs from many other incidents in that it provides not a gradual, but, usually, a “salvo” load on the environment, requiring fast responsive reaction.
Among the methods which are successfully used to solve the problem of the liquidation of the results of pollution is sorbate purification of water. The advantages of the sorbate method can include the ability to remove pollution of practically any kind to achieve any final concentration, and also the ability to control the process.
Currently, for the purification of the water surface from oil products and other hydrocarbonic products, both natural sorbents, which have certain advantages, and different synthetic sorbents are widely used. Taking into account modern requirements for these kinds of materials, some of the main qualifications which such sorbents should possess are: high specific surface of material, which increases its contact with the pollutants and which, at the same time, provides for effective absorption; low specific mass, which guarantees enough floating of the adsorbent, including after its contact with the pollutants; and the ability to effectively remove sorbent from the water surface together with adsorbing pollutants. Synthetic porous polymeric materials also possess the distinctive ability to change porosity within a wide range, while having the same chemical structure.
In one synthetic sorbent, the powder of elastoplastic block-copolymers of styrole with ethylene and butylene is used as the absorbent. Liquid oil is covered with the powder polymer, is soaked up by it, and a light, hard material with a non-oily and non-sticky surface is gathered and removed from the surface of the water. The technological difficulty of gathering of the absorbent form the surface of the water and impossibility of regeneration are some of the disadvantages of this method.
In another synthetic sorbent, fibrous material made from polypropylene and modified basalt fiber coated with surface-active material (monoalkyl ethers of polyethylene glycol and monoalkylphenil ethers of polyethylene based on a polymer distillate) is used to remove thin oil plaque from the water surface. Some disadvantages of this method are the impossibility of regeneration of the absorbent and restrictions on the thickness of the removed plaque.
A sorbent based on a fibrous cellulose material, coated with block-copolymers styrole with butadiene, has been developed in order to gather oil and oil products. A sorbent with magnetic qualities was reported using iron chloride, iron shavings and chrome-containing washing waters with an ion ratio of Cr (VI)/Fe (III) 1:1. This sorbent is primarily designed to purify waste waters from the ions of heavy metals and it does not have flotation ability and mechanical durability.
The macroporous sorbent-copolymer styrole with divinylbenzene (40%), obtained by the method of suspension polymerization, is used for sorbent removal of multi-component organic compounds from water mixtures when processing large volumes of waste waters. This sorbent does not possess magnetic qualities and cannot be used for removal of the oil pollution from the water surface.
A highly porous sorbent with good flotation ability, which provides it with high sorbate qualities, was developed on the basis of the high-molecular polyethylene, the active part of which is composed of natural aluminum silicate. This sorbent, in general, is used to purify water environments from radionuclides of cesium and it does not possess magnetic qualities.
In order to remove oil and its products from the water surface, sorbent with flotation ability and high absorbing ability with respect to oil and its products, which includes lightly crosslinked vulcanizate, based on the isoprene rubber and vulcanizing system, and latex foam rubber, was developed. However, this sorbent does not possess magnetic qualities, which make its removal from the water surface difficult.
Nowadays, sorbents based on sewn and over-sewn polymers, which have good porousness, high mechanical durability and high sorbent qualities, are widely used. Highly-porous sorbents based on over-sewn polystyrol, which are successfully used in different means of purification and removal of chemicals for medical purposes, in the pharmaceutical industry, in cosmetics (production of phospholipids, nucleic acids, extraction of saponins), and also in chromatography and production of bio- and hemocompatible sorbents, are known.
For adsorption of oil and organic dissolvents from fresh- and seawater, a product of special cross-cut stitching in chlorinated hydrocarbon with a sewing agent and a catalytic agent of polystyrol, a triple copolymer of sterol, ethylene and butadiene is used. However, the absence of magnetic qualities of the sorbent makes it difficult to remove it from the water surface after its saturation with the oil products.
In known references, the problem of removal of toxic substances from water and gas environments is solved with the help of a porous granulated sorbent, which includes a polymer matrix, based on a porous granulated ionic (polystyrol, epoxypolyomid, vynil pyridinic matrix) and iron hydroxide. The abilities of this sorbent for removal of oil products from the water surface are limited by the absence of magnetic qualities, low mechanical durability and flotation ability.
Magnetic porous sorbents might contain hydrophobic polymer binding medium in the shape of granules or powder (polyethylene, polypropylene, polystyrol, mix of polyethylene granules and copolymer ethylene with vynil acetate, mix of butadiene-neutral rubber and polyethylene (or polystyrol and vynilchloride)), magnetic filler, mineral oil and aluminosilicate porous filler, modified by hydrophobizated organosilicone liquid.
A porous sewn or over-sewn polymer (sewn polyolefin foams, polyvinyl chlorides, polymers and styrole copolymers) is known with the sewn ratio of no less than 60%, with specific surface of 800-1900 m2/g, with the use of magnetic filler with the size of a particle ranging from 1 to 10 mkm. Acting as the porous polymer matrix, the sorbent can contain sewn polymer, obtained through copolymerization in the mixture using bi-functional compounds acting as sewn agents (for example, 4,4 bischlorometyldefinyl, xylendichlorid, monochloridemethyl ether).
Oversewn polystyrol can be used as the polymer matrix, obtained through swelling of styrolediynilbenzole copolymers in the chloro-containing organic liquid, addition of bi-functional compounds, which interfere in accordance with Friedel-Crafts reaction, by heating of the reacting mixture, filtration and cleansing of the polymer with the ratio of bi-functional compound to copolymer styrole at (0.5-1):1, and by heating at 70-140° C. for 6-11 hours. Foaming is performed either before sewing of the polymer matrix, or after receipt of the sewn polymeric structure (foaming with back-pressure). Magnetic sorbent is prepared by means of consecutive swelling of polymer matrix in the dissolvent at 50-70° C., followed by its saturation while in swollen state with magnetic filler, which fills part of the channels of the polymer matrix. Nano-particles of metallic iron are prepared by means of regeneration of compound of iron with hydrogen (at 250-400° C.) with subsequent stabilization in 0.1-0.5% solution of oleic or stearic acid. The multistage nature of the production process and the necessity to use high temperatures are some of the disadvantages of the process.